import random
stu = []
for c in 'ABCDEFJ':
    yz = (c, random.randint(40, 100))
    stu.append(yz)

print(stu)
score = sum([s[1] for s in stu])
print('平均分：', score/len(stu))
stu2 = [s for s in stu if s[1] < 60]
print('不及格人数', len(stu2))
